Small Craft Advisory 72, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
101 PM CDT Fri Aug 14 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Scattered showers (30-55%) late tonight through Saturday
  afternoon. Latest trend is downward for rain chances and rain
  amounts on Saturday.

- Another round of showers (30-50%) and a few thunderstorms
  (10-20%) Saturday night as cold front moves through. Locally
  heavy rain possible.

- Drying out later Sunday into Monday with next chance for showers
  and some storms Tuesday into Wednesday.

&&

.DISCUSSION...
Issued at 140 AM CDT Fri Aug 14 2026

Day today, some showers arrive late tonight: Weak high pressure
overhead with pockets of mid cloud and locally dense fog. Thus far
the fog is variable in coverage to have anything more than SPS
out, but will monitor to see if a Dense Fog Advisory is needed
anywhere. A lull in cloud cover this morning, then clouds increase,
thicken late today ahead of southern stream shortwave that arrives
late tonight. Easterly winds result in warmest readings today
central to north-central WI with highs in the lower, maybe mid
80s. Few showers make it into southern tier of counties very late
tonight ahead of the wave.

Showers/Storms Saturday and Saturday night: Trend that is emerging
is most guidance (except especially the NAM) is to keep majority
of widespread showers on Saturday to the south closer to the
higher instability and convergence on nose of LLJ. This shows up
nicely when looking at HREF 1hr probs of 0.01" which shows higher
probabilities staying over far southern WI, northern IL during
the morning. Increasing moisture and lift on the north edge of
this could still produce scattered showers, with the greatest
focus southern Fox Valley to the lakeshore. If this trend continues
though, some locations could stay dry during the daytime on Saturday,
which looked very unlikely a couple days ago. Main front does
swing through on Saturday night with primary shortwave over Lake
Superior. This is likely when most locations will see at least
scattered showers. Given boundary is interacting with PWATs over
1.8" (95+ percentile) and slower MBE vectors are forecast,
locally heavy rain may occur Saturday night.

Dry later Sunday into Monday: Front clears eastern WI by Sunday
morning. A few showers may linger during the morning, but mainly a
dry day is expected. Looks kind of breezy with peak gusts over 20
mph at times as winds shift northwest. Despite being behind the
front, it could actually be warmer on Sunday with more sunshine
and mixing. Not as humid as Saturday, but dewpoints will still
linger into the mid 60s over east-central most of the day. Monday
will be noticeably less humid across the board.

Next chance for rain is Tuesday...Northwest flow brings another
shortwave trough and cold front through leading to next chance
for organized showers and some thunder Tuesday. Greatest instability
Tuesday afternoon remains southwest of our area, so risk for
severe storms looks lower which aligns with various ML
projections that shows greater signal southern MN into IA.
Models/ensembles are picking up on another wave sliding in from
the west interacting with the frontal boundary to keep showers and
some storms lingering later Tuesday night into Wednesday. With
PWATs up to 1.5 thrown into the mix, probabilities of 0.5 inch/1.0
inch of QPF have steadily increased over the last few runs. ECMWF
EFI/SOT now has some signal for heavy rain. WPC is also now
indicating a Marginal to Slight (level 1/2 of 4) for excessive
rain during this time. As we saw with the evolution of this weekends
higher risks that eventually shifted south, these areas can shift
with time, but will be something to watch as we get closer to this
time frame.

Cooler air push behind this system for the end of the week with
highs settling into the lower to middle 70s.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 101 PM CDT Fri Aug 14 2026

Light, generally easterly winds continue through early tomorrow.
Mid-level clouds will gradually increase overnight becoming BKN
to OVC at times. A few scattered rain showers may move into the
area overnight and Saturday morning, but most areas are expected
to remain dry so precipitation was not mentioned. Generally VFR
conditions are expected across the area through the period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION.....JLA
AVIATION.......KS

Hazardous Weather Outlook
National Weather Service Green Bay WI
915 AM CDT Fri Aug 14 2026

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-151415-
Vilas-Oneida-Forest-Florence-Northern Marinette County-Lincoln-
Langlade-Menominee-Northern Oconto County-Door-Marathon-Shawano-
Wood-Portage-Waupaca-Outagamie-Brown-Kewaunee-Waushara-Winnebago-
Calumet-Manitowoc-Southern Marinette County-
Southern Oconto County-
915 AM CDT Fri Aug 14 2026

This Hazardous Weather Outlook is for north-central and northeast
Wisconsin.

.DAY ONE...This Afternoon and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

There is a slight chance for thunderstorms with brief, locally
heavy downpours Saturday night into early Sunday morning.

The next chance for thunderstorms will be Tuesday afternoon into
Wednesday. The potential for severe weather is low, but locally
heavy rain could occur.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed this afternoon or tonight.

LMZ521-522-541>543-151415-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
915 AM CDT Fri Aug 14 2026

This Hazardous Weather Outlook is for portions of northwest Lake
Michigan and the waters of Green Bay.

.DAY ONE...This Afternoon and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Conditions may become hazardous for small craft south of Kewaunee
on Saturday.

There is a chance for thunderstorms Saturday night into early
Sunday, then again Tuesday afternoon into Wednesday. Any thunderstorm
could pose a hazard to mariners.

KS